International Patent Publication WO02/22763 A1, published Mar. 21, 2002, (assigned to RESEARCH TRIANGLE INSTITUTE) describes sulfur removal sorbents and processes for their preparation and use. The sulfur removal technology and sorbents of WO02/22763 A1 disclose the treatment of hydrocarbon fuels, particularly diesel and gasoline fuels, to reduce sulfur contaminants to less than about 30 parts per million by weight (ppmw), for example, to 15 ppmw or less. In particular, a normally liquid hydrocarbon fuel or fuel component, such as an FCC naphtha, FCC light cycle oil, coker distillate, straight run diesel fraction, or the like, is treated at an elevated temperature, preferably a temperature above about 300° C. (572° F.), with a sorbent comprising an active metal oxide sulfur sorbent, such as a zinc oxide, iron oxide, zinc titanate or the like, in the absence of an active hydrodesulfurization (HDS) catalyst, to reduce sulfur contaminant levels to less than about 30 ppmw, sulfur. The sorbents preferably include a refractory inorganic oxide cracking catalyst support such as alumina, an aluminosilicate or the like, in combination with the metal oxide sulfur sorbent. Metal-substituted inorganic oxide cracking catalyst support such as metal aluminates, e.g., zinc aluminate, iron aluminate, are among the preferred supports.
The desulfurization technology of Patent Publication WO02/22763 A1 can achieve substantial reductions of cyclic and polycylic organic sulfur contaminants in various feedstocks such as hydrotreated FCC naphtha and hydrotreated diesel blends and components to reduce their sulfur content to below 30 ppmw, or less, while avoiding or minimizing the problems traditionally associated with cyclic sulfur contaminant removal. Such traditional problems have included high hydrogen consumption associated with olefin and aromatic saturation, product yield losses and/or increased processing costs associated with HDS processes. In one embodiment, the sorbents and desulfurization processes of Patent Publication WO02/22763 A1 are employed in a polishing step for removal of sulfur contaminants, particularly cyclic and polycylic organic sulfur contaminants, from relatively low-sulfur feedstocks including low-sulfur hydrocarbon fuels, fuel components or fuel precursor feeds.
Regeneration of the sorbents is achieved by contacting the sorbent with an oxygen-containing gas, preferably air, at a temperature sufficient to cause the sulfur present on the sorbent to react with oxygen to form sulfur dioxide. Typically, the equilibrium temperatures in the regeneration zone exceed a temperature of about 425° C. (800° F.).
The entire disclosure of the aforesaid International Patent Publication WO02/22763 A1 is hereby incorporated herein.